Association of Left Atrial Size with Atrial Fibrillation in Rheumatic Mitral Stenosis

Objective: To determine the association of Left Atrial (LA) size with atrial fibrillation (AF) in patients with Rheumatic Mitral Stenosis. Study Design: Analytical Cross-sectional study. Place and Duration of Study: Adult Cardiology Department, Armed Force Institute of Cardiology/National Institute of Heart Diseases, Rawalpindi Pakistan, from Aug 2023 to Mar 2024. Methodology: One hundred and twenty-eight patients with an age range of 20-60 years who were diagnosed with rheumatic mitral stenosis based on echo findings were included via consecutive sampling technique. Left atrium size, mitral valve area, and left ventricular ejection fraction were measured with a transthoracic echocardiogram (TTE) to assess the severity of stenosis and the risk of atrial fibrillation. Results: Out of 128 study participants, 73(57.0%) were females, whereas 55(42.3%) were males and mean age was 44.52±11.88 years. The median size of the left atrium and mitral valve area was 47.00(42.00-51.00) mm and 1.04(0.83-1.30) cm2 respectively. Atrial Fibrillation was reported in 86(67.2%) patients, and majority of them 85(98.8%) had LA size >40mm, while 26(61.9%) out of 42 patients with no AF had LA size >40mm (p<0.001). Patients with AF also showed lower median ejection fraction (55.00% vs 60.00%) and higher mean values of age and median LA size (47.25±10.22 vs 38.92±13.17 years; 49.00mm vs 42.00mm respectively) compared to those who had no AF (p<0.01). Conclusion: Left atrial enlargement is significantly associated with development of atrial fibrillation in patients with rheumatic mitral stenosis.